Question

find the total surface area of a cuboid of length 10cm,breath 8cm and the height 6cm

Answer 1

I think you should try these two formulas:
(lb)+(bh)+(hl)
l×b×h

Answer 2

total surface area of a cuboid is 2×(lb+bh+lh) so ,total surface area is 2×((10×8)+(10×6)+(6×8))
which is 460800 cm.